Hi,
AntC's f can be done without -XOverlappingInstances
http://lpaste.net/7559485273839501312, using the trick didn't work in
#9918. I'm not sure extra syntax is justified to clean up this rare case.
Regards,
Adam
On Sun, Jun 7, 2015 at 11:12 AM, Dan Doel dan.d...@gmail.com wrote:
It
On Jun 2, 2015 6:03 PM, Wolfgang Jeltsch g9ks1...@acme.softbase.org
wrote:
Hi,
bug #10009 appears on the status page with status “new”, although the
bug should have been fixed in HEAD. Can this fix *please* be a part of
GHC 7.10.2? At the moment, this bug breaks the incremental-computing
Hi Wolfgang,
https://ghc.haskell.org/trac/ghc/ticket/10009 might be the same regression
(fixed in HEAD)
Regards,
Adam
On Tue, Jun 2, 2015 at 12:28 PM, Wolfgang Jeltsch
g9ks1...@acme.softbase.org wrote:
Hi,
the following (contrived) code is accepted by GHC 7.8.3, but not 7.10.1:
{-#
Hi Sergei,
I think you should use {-# OVERLAPPABLE #-}: see the description here
https://ghc.haskell.org/trac/ghc/ticket/9242#comment:16 which is probably
in the manual somewhere too.
Regards,
Adam
On Thu, May 21, 2015 at 9:40 AM, Sergei Meshveliani mech...@botik.ru
wrote:
People,
I wrote
Hi Ben,
With ghc-7.8.4 I get a different error Empty record update of:
default_config when using a wildcard to update a record.
I think you can't use wildcards in record updates because it's harder
(for users and for ghc) to figure out which fields are involved when
you don't name a constructor.
Hello list,
The following file compiles with my plugin. It makes a data family
HList have role representational in a way that I believe is safe:
https://github.com/aavogt/HListPlugin/blob/master/ex/Coerce.hs#L19
I expect the highlighted line to be acceptable. However, it seems that
the plugin
What part of applicative-quoters is broken for you? 0.1.0.8 compiles
on ghc-7.8.4 here, and [ado| a - Just (); b - Just 2; (a,b) |]
evaluates to Just ((),2) as it should.
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Hi Adam,
I've added a README which tries to explain things:
https://github.com/aavogt/HListPlugin
When I produce a wanted constraint from a wanted constraint, things
work as I wanted. Thanks for the suggestion!
Regards,
Adam
On Mon, Feb 16, 2015 at 4:36 AM, Adam Gundry a...@well-typed.com
Hello,
Using ghc-7.10 rc1, I am trying to write a type checker plugin that
adds wanted constraint which helps ghc to infer more types. However,
it seems that the wanted constraints I add don't get added to the
inferred type of the declaration, so that I get a type error like:
a.hs:1:1: Warning:
On Tue, Feb 10, 2015 at 6:38 AM, Jan Stolarek jan.stola...@p.lodz.pl wrote:
I don't know how realistic this is but a constraint (HLength x ~
HLength y) would ideally have the same result as SameLength x y.
I'm not sure if I understand that part. HLength is not injective. How would
injectivity
Hi Jan,
One example is https://github.com/haskell/vector/issues/34
I see lots of potential uses in HList. For example in HZip.hs there's
a Zip using type families:
type family HZipR (x::[*]) (y::[*]) :: [*]
type instance HZipR '[] '[] = '[]
type instance HZipR (x ': xs) (y ': ys) = (x,y) ':
Hi Greg,
Perhaps a less-invasive way to implement the -XSafe part of your
proposal would be to provide a module like:
module Language.Haskell.TH.Safe (
module Language.Haskell.TH,
reifyWithoutNameG,
) where
import Language.Haskell.TH hiding (runIO, reify*)
where reifyWithoutNameG is the
I've added it as https://ghc.haskell.org/trac/ghc/ticket/10009
On Tue, Jan 20, 2015 at 11:23 AM, Richard Eisenberg e...@cis.upenn.edu wrote:
After quite a bit of thought, I agree that this is a regression and that the
original program should be accepted.
Make a bug report!
Thanks,
Richard
Hello List,
With ghc - 7.8 and 7.6 the following program is accepted:
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
class (UnF (F a) ~ a, Show a) = C a where
type F a
f :: F a - a
type family UnF a
g :: forall a. C a = a - String
g _ = show a
where a = f
Hi Volker,
You can use this extension:
http://www.haskell.org/ghc/docs/latest/html/users_guide/deriving.html#stand-alone-deriving
to write that orphan Typeable instance for most ghcs (probably 6.10 is
the earliest).
It might be worth pushing for a Typeable instance to be added to the
unix
Zeroth takes the first approach. It only supports a subset of TH
(DecsQ splices) however.
http://hackage.haskell.org/package/zeroth
https://github.com/aavogt/zeroth is a fork that works with more recent
haskell-src-exts and ghc
On Sat, Jul 5, 2014 at 3:59 PM, John Meacham j...@repetae.net
Hello List,
Given the following definitions:
class HEq (x :: k) (y :: k) (b :: Bool) | x y - b
instance ((Proxy x == Proxy y) ~ b) = HEq x y b -- (A)
instance ((x == y) ~ b) = HEq x y b -- (B)
The instance (A) lets HList compile, which can be reproduced with:
darcs get
] GHC generally obeys this rule
]
] · If GHC infers a type f::type, then it’s OK for you to add a type
] signature saying exactly that.
That rule suggests that -XScopedTypeVariables should be on by default,
and that you shouldn't need a forall to bring the type variables into
scope. I
http://www.haskell.org/ghc/docs/7.8.1-rc2/html/users_guide/syntax-extns.html#explicit-namespaces
is the trick
On Sat, Mar 15, 2014 at 12:47 PM, Henning Thielemann
lemm...@henning-thielemann.de wrote:
I want to import Nat and type-level (=) from GHC.TypeLits:
import GHC.TypeLits (Nat, (=))
Hello Christian,
It seems new to me that $( ) is allowed in patterns. I would have used
lamE in something like:
[| $(varE v) = return . SM.concatMapM $(lamE [varP v] (buildRns f
(xs++[w]) ys))) |]
Regards,
Adam
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Hi Merijn,
Let me suggest the Fail type family in
http://www.haskell.org/pipermail/haskell-cafe/2013-November/111549.html
--
Adam
On Tue, Jan 14, 2014 at 8:56 AM, Merijn Verstraaten
mer...@inconsistent.nl wrote:
I was trying to fix one of my closed type families examples for the new
syntax,
Hello,
I have code:
{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses,
ScopedTypeVariables, TypeFamilies #-}
class C a b where c :: a - b
instance (int ~ Integer) = C Integer int where c = (+1)
c2 :: forall a b c. (C a b, C b c) = a - c
c2 x = c (c x :: b)
c2 x = c ((c :: a - b) x)
Why
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